1. Field of the Invention
The present invention relates to a cleaning sheet which is intended to be used for cleaning as attached to a mop-like cleaning device or the like, and more particularly to a cleaning sheet which can absorb and retain liquid.
2. Description of the Related Art
There have been known cleaning sheets which should be used for cleaning the house floor as attached to a cleaning head of a mop-like cleaning device. Such conventional cleaning sheets are typically constructed of a single nonwoven fabric or by layering two or more nonwoven fabrics on top of one another and used in a dry state. When they are used in a dry state, dirt or dust can be trapped between fibers on the surface of the nonwoven fabric. Alternatively, an adsorbent lubricant is coated thereon to let dirt or dust adhere to the sheet surface.
However, such cleaning sheets to be used in a dry state are not effective in removing stains adhered to the floor surface, although they are effective in collecting fluffy dust.
Japanese Utility-Model Registration No. 3094858 discloses a cleaning device which has nozzles in a cleaning head for squirting water to the floor surface. After wetted with water, the floor surface is wiped off with a cleaning sheet attached to the cleaning head. Japanese Unexamined Patent Publication No. 2001-521432 also discloses a cleaning device with a liquid supply part on a handle which extends upward from the top face of a cleaning head.
The cleaning devices disclosed in the above-identified documents are used such that the nozzles provided in the cleaning head apply water or cleaning liquid to the outside of the cleaning head, and the floor surface wetted with the water or cleaning liquid is then wiped off with a cleaning pad. The cleaning pad, which is designed to be attached to the bottom face of the cleaning head, has a liquid permeable sheet on a cleaning surface side to be applied to the floor surface, or the like, and a liquid absorbent layer behind the liquid permeable sheet. It should be noted that the back side of the cleaning pad, which faces the cleaning head, is typically covered with a liquid impermeable sheet.
However, in the case where the cleaning head is provided with the nozzles, as in Japanese Utility-Model Registration No. 3094858, if the water or cleaning liquid flows down the cleaning head after being squirted out of the nozzles, it tends to spread between the cleaning head and the cleaning pad. Because the back side of the cleaning pad is impermeable to liquid, the water or cleaning liquid tends to remain between the cleaning head and the cleaning pad. When the cleaning pad is removed from the cleaning head, the water or cleaning liquid drips on the floor surface, and the cleaning head after removal of the cleaning pad remains soaked with the cleaning liquid.
Moreover, if the cleaning liquid remains between the cleaning head and the cleaning pad, the coefficient of friction between the cleaning head and the cleaning pad may be decreased and cause slippage between the back side of the cleaning pad and the cleaning head when the cleaning pad is slid on the floor surface.
In Japanese Utility-Model Registration No. 3094858, furthermore, the liquid is directly applied to the floor surface from the nozzles of the cleaning head. If the floor surface to be cleaned is a ceramic tile floor, a large amount of liquid may be directly applied to the floor surface without any problem, but if the floor surface is a wooden floor on which a finishing compound such as a paint is applied, a large amount of cleaning liquid may deteriorate the finishing compound.